The invention pertains to a keyboard instrument for the natural tone system.
While conventional musical compositions are primarily based on the tempered tone system, microtonal compositions are predominately based on the so-called natural tone system. The term natural tone system or natural tone series represents the succession of overtones that are defined as an integral multiple of the fundamental frequency of a tone: EQU f(n)=f(o).times.n, with n=1, 2, 3 . . .
In this formula n is also designated as the natural tone number.
As compared to the overtone series, the fundamental tone in a natural tone series is already designated as the first natural tone. It is characteristic for the natural tone series or the natural tone system that an octave shift is always produced by a power of 2.
It is basically possible to form arbitrary natural tone series on any desired fundamental frequency. To compose sensibly and perform using the natural tone system, it is necessary however to make a selection. This selection suggests that only the tones of a natural tone series defined by a certain fundamental frequency and their octaves are permitted as fundamentals. This results in natural tone series selected with reference to a so-called modulation factor m in accordance with the natural tone number as follows: EQU f(n,m)=f(o).times.n.times.m, with n,m=1,2,3 . . .
The smaller the modulation factor, the larger the number of tones which the selected series has in common with the original natural tone series.
The invention is based for practical reasons on the aforementioned selected natural tone series. However, the invention is not limited to these selected natural tone series.
All types of conventional instruments, which also include keyboard instruments, are basically suitable for microtonal music. One problem with the performance of microtonally composed music on keyboard instruments can be seen in the fact that keyboard instruments are designed for the tempered tone system outlined in the subclaims.
While the aforementioned keyboard instruments for the natural tone system thus far used conventional keyboards or personal computer keyboards designed for the tempered tone system consists of, the invention suggests that the number of keys per octave be increased to 16, and that their arrangement be designed such that the natural tones 4-7 (24), 8-15 (25,34) and 16-31 (26,35,40,41) are played in series on three playing levels.
The invention thus provides a special new keyboard for the pure intervals contained in the natural tone scale which not only meets the requirements of the natural tone series, but is also compatible with the performance technique already learned for keyboard instruments, so that playing on the keyboard instrument according to the invention can also be easily learned by persons accustomed to conventional keyboard instruments.
The ability to play the keyboard instrument according to the invention on three playing levels is attained by three different forms of keys, namely by "harmonic keys" that tapered twice from the front toward the rear, by "melodic keys" tapered only once, and by "chromatic keys" with uniform width. These keys are arranged relative to each other in such a way that only the front sections of the "harmonic keys" with a maximum width are located adjacent to each other in the front field or front playing level. In the central field or central playing level, the sections of the "harmonic keys" that correspond with the first tapering adjoin the front sections of the melodic keys with the same width, and are thus represented alternately with the harmonic keys in the central field. The rear field or rear playing level is formed by the sections of the "harmonic keys" that are tapered for the second time, the tapered sections of the "melodic keys" and the "chromatic keys" with uniform width, namely in the regular series: "harmonic key," "melodic key" and "chromatic key." It is essential that the adjacent key sections are equally wide and equally long or deep within each playing level.
In other words, the structure of the keyboard of the keyboard instrument according to the invention provides at least three differently shaped types of keys in order to realize the different playing levels or key fields, namely a first type of key which extends over the entire depth of the keyboard and has a given maximum width in the frontal section, whereby the maximum width can, for example, correspond to the width of the keys on conventional keyboards. Within the area of the harmonic tones (n,m=4,5,6,7) this type of key can continuously have the aforementioned maximum width. This type of key has a central section of reduced width, preferably half the maximum width, at least within the area of the melodic tones (m,n=8 to 15). A second type of key which is recessed against the first type of key is arranged within this tone area, whereby the recessed keys have their largest width in the central area of the first mentioned type of key, and their width is strongly reduced in the rear section of the field of the chromatic tones (n,m=16 to 32) located adjacent to the melodic tones, whereby the section with strongly reduced width lies adjacent to a correspondingly smaller section of the first mentioned type of key as well as a third type of key which is constructed similar, preferably equally narrow.
At least within the area of chromatic tones, the first type of key thus comprises keys with a frontal area of maximum width, a central area of reduced width, preferably half the maximum width, and a rear section with a further reduced width that preferably corresponds to a quarter of the maximum width. The second type of key has two differently wide areas at least within the area of the chromatic tones, namely a frontal width that preferably corresponds to half the maximum width, and a rear section of reduced width that preferably corresponds to a quarter of the maximum width. As compared to these two types of keys, the third type of key which is exclusively arranged within the area of chromatic tones preferably has one single width, namely a width that corresponds to a quarter of the maximum width.
Finally, keys for the microchromatic tones (n,m=33 to 64) can adjoin the area of chromatic tones, that is, preferably arranged to the right of the keys that correspond to the chromatic tones. These keys which preferably have a width which corresponds to an eighth of the maximum width are preferably constructed as sensors and lie in a preferred doubled example of the aforementioned keyboard structure within the area of the recessed sections of the keys assigned to the harmonic tones.
The keys of the keyboard according to the invention thus provide the possibility of playing natural tones in series. All keys preferably have the same height; this means that no key protrudes over another one, so that glissando playing can be performed.
The wedge shape of the keys suggested according to the invention in the tapered area ensures an even distribution of the playing surfaces and in turn provides substantial advantages in regard to the performance technique.
While the keyboard of the keyboard instrument according to the invention is preferably a manual, which means a keyboard that is played manually, it is basically also possible to utilize this keyboard with keys activated by the feet as is customary with an organ.
While a scale change can be executed by activation of a push button in the conventional manner (see keyboards of electronic keyboard instruments), the keyboard instrument according to the invention utilizes a second manual which is structured similar to the first manual and into which the new fundamental can be entered. Both manuals can be switched parallel with the aid of a special coupler.
The additional manual furthermore makes it possible not only to quickly change the scales, but also to arbitrarily combine the manuals during simultaneous play, which in turn provides a substantial expansion for the playing of natural tones. It is, for example, possible to not only combine two overtone series with m=1,3,5,7,9,11,13,15, in any desired manner, but also to combine overtone and undertone series with each other by switching one manual to the undertone series; thus the following combinations are possible:
______________________________________ 1) I: Overtone series 3) I: Undertone series II: Undertone series II: Overtone series 2) I: Overtone series 4) I: Undertone series II: Overtone series II: Undertone series ______________________________________
Even couplings between the manuals are possible. This means that altogether 140 combination possibilities can be realized.
An octave shift of the tones on one manual of the keyboard instrument according to the invention is preferably made possible by depressing a special key. A reversal of the fundamentals can be particularly easily realized, whereby the fundamental is, for example, octave shift on one of the manuals (for example the lower manual). One adjusting wheel per manual is furthermore provided in order to quickly shift the instrument. This means that the tonal range of the instrument can be enlarged without any problems, whereby the distances can be increased by octave shifts if undesirably dense sound combinations of different scales occur.
Surprising sound effects can be obtained by the addition of pre-programmable mixtures. By entering 3-3-2, the tone played is supplemented by overtones within the predetermined intervals; the following sound combinations can be played:
______________________________________ tone played 8 9 11 10 11 12 14 13 14 total sound 15 17 16 16 17 19 18 ______________________________________
Mixtures of both manuals can furthermore be combined or coupled with each other.
______________________________________ 16 8 22 1st manual 11 24 8 2nd manual m = 2 14 28 10 m = 3 18 30 13 36 16 39 48 total sound ______________________________________
Undertone scales are thus far used relatively little in compositions because of the lack of suitable keyboard instruments. The keyboard instrument according to the invention allows a practical realization of undertone scales whose melodic tone series can be recognized, although they are ficticious when played polyphonically. Since the same keys can basically be utilized for the undertone scales, all that is really necessary is to alter the colors of the keys. While the harmonic keys third and seventh are for example, normally blue and green, the lower tone series can be indicated optically, for example, by the fact that the two aforementioned keys remain blue, while the seventh of the overtone or undertone series is underlaid with yellow which can, for example, be done by an appropriate illumination of the keys.
The invention is described in detail in the following with the aid of the figures. They show: